1912.] NATURAL SCIENCES OF PHILADELPHIA. 137 



phosphorus, chlorine, and sulphur by methods in general similar to 

 those described by Katz in the Archiv fur die gesammte Physiologie, 

 1896, Vol. LXIII, pp. 1 et seq. At least two determinations were 

 made in the case of every element; and in no case, except that of 

 sodium, did the parallel determinations differ from each other by 

 more than 15 per cent. In the case of sodium, one determination 

 was about 24 per cent, higher than the other. The following are 

 the average amounts of the elements found, given as per cent, of the 

 fresh tissue: Potassium, 0.3250; Sodium, 0.0726; Iron, 0.0007; 

 Calcium, 0.0042; Magnesium, 0.0129; Phosphorus, 0.1372; Chlo- 

 rine, 0.1195; Sulphur, 0.1612. Six determinations were made of 

 the water and total solids. The averages were solids, 17.70 per cent. ; 

 water, 82.30 per cent. The widest differences were solids I, 17.39 

 per cent.; solids VI, 17.99 per cent. 



Parallel analyses of the ash of the striated muscle of the same 

 frogs were made, and the results obtained were quite close to those 

 reported by Katz for frog's striated muscle. The work indicates 

 that smooth muscle contains somewhat less potassium and phos- 

 phorus and considerably more sodium and chlorine than striated 

 muscle, but the differences are much less marked than has sometimes 

 been supposed. 



The chemical work was supplemented with microscopic study of 

 fixed and fresh samples of the tissue analyzed as "smooth muscle," 

 and it was found that about 80 per cent, of its volume was smooth 

 muscle fibre; about 5 per cent, extraneous connective tissue; and 

 the remainder, interstitial spaces between the muscle fibres. 



Marshall A. Howe, Ph.D.: "Reef -building and Land-forming 

 Seaweeds." Beautifully illustrated. 



That the corals and other lime-secreting animals are active agents 

 in building reefs and forming land has been a matter of common 

 knowledge and belief for more than half a century, but that certain 

 marine algse or seaweeds also have an important and sometimes 

 predominating part in the same great work has received no par- 

 ticular emphasis until quite recent years. Most people think of 

 sea plants, if they think of them at all, as small delicate ornamental 

 "sea-mosses" or as coarse, succulent, not especially attractive, kelps 

 or rockweeds, having in either case, little solid substance to be left 

 behind on their decay. The fact is, however, that there are many 

 different kinds of marine plants that secrete lime from the sea water 

 and are more or less hard and stone-like, so that their decay or their 

 continued upward growth is accompanied by a considerable increase 

 in the height of the sea bottom wherever these plants happen to be 

 growing. The corals are, generally speaking, confined to the warmer 

 seas, but the corallines, lime-secreting marine plants with a superficial 

 resemblance to the corals, are more widely distributed, having, in 

 fact, been found to be very abundant more than 12° north of the 

 Arctic Circle. The late Professor Kjellman, of Upsala, has stated 

 that off the shores of Spitsbergen and Nova Zembla a certain coral- 



